SEISMIC PERFORMANCE ASSESSMENT AND RETROFIT OF YENIBOSNA BRIDGE

Cem Özaydın

(Thesis Supervisor: M. Nuray Aydınoğlu)

ABSTRACT

Yenibosna Bridge is a life line structure of the 1' Peripheral Motorway of Istanbul (E-5) and its one of the structures that has a seismic performance lower than desired. The performance 1 level of serviceability limit state under the deterministic ground motion (Sl) and damage control limit state under probabilistic ground motion (S2) should be satisfied. The purpose of this study is to evaluate the seismic performance of the Yenibosna Bridge, and to seismic retrofit the existing bridge to mitigate the risk that currently exists. Preliminary screening of the bridge shows that the bridge is generally in good condition can be considered consistent with the project drawings but there is a major drainage problem and bearings on the abutments are out of their sitting pad. The bridge is modeled with h e elements and capacity of existing cross-sections is calculated with pushover analyses, Second the bridge model is updated with new dimensions of piers with concrete jackets and stiff nesses of new larger elastomeric bearings. Capacity of bridge re-analyzed in longitudinal and transversal directions. Results of pushover analyses checked Mth re-analyzing the bridge model with nonlinear time history . Analyses show that capacities of the structural members of the bridge under the given performance levels satisfy the demand of the earthquakes after retrofitting.